As the most common external storage device, a hard disk is used for storing information of operation systems and a great amount of data, thus its safety and reliability is of great importance. But all the misoperation of users, the defects in hard disk data management software, and the attack of computer viruses may destroy the useful data in the hard disk. So backup of the hard disk data is very important to ensure that some critical data contents can be recovered when necessary.
One of the existing hard disk data backing up methods is to back up the information of a partition or a hard disk as a file, and to open the file during recovery to recover the backed contents into the original partition or hard disk. This backing up method is based on a file system, and once that file system is damaged, the partition where the backed file is stored is deleted due to the attack of viruses, or the partition is damaged so that the file can not be read out any more, then the backed information would be impossible to be recovered. Since such a backup depends on the integrality of the partition where the backed file is stored and the integrality of the backed file itself, the safety of this kind of backup is not guaranteed.
In the existing hard disk data backing up methods, both the backing up and the recovery have some limitations, i.e., either the whole hard disk or a partition is backed up, and the recovery can only be done according to the mode which is taken during the backup. But if a user has different requirements, for example, sometimes the user wants to recover the whole hard disk, while sometimes the user just wants to recover one partition. However, the backup mode for a whole hard disk would not allow the recovery of only one partition thereof, and the backup mode for a partition would not allow the recovery of the whole hard disk. Thus, if both partition and whole hard disk recovering capabilities are required, two backups are needed: one in partition mode, another in whole hard disk mode, which will result in redundance of backup operation, and produce not only waste of human power and time, but also waste of the space in the hard disk.